Materials, Methods and Compositions for a Composite Building Material

ABSTRACT

A solid composite material is suitable for construction and industrial uses. The solid composite material consists of at least an effective amount of assorted agricultural remnants bound in an effective volume of cured resin.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of Provisional U.S. Patent Application 61/086,058, by the same inventor and filed Aug. 4, 2008, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates generally to composite construction materials and more particularly to a combination of plant remnants and resin to form a cured composite having high tensile, compression and flexural strength without heat curing and which can be formed into a wide variety of shapes, contours and finishes.

BACKGROUND

Composite panels are usually made of wood, agriculture or other fibers by a manufacturing process leading to a production of panels in the form of hardboard, oriented strand board, fiber board siding, wafer board, medium density fiber board, particle board, and other similar boards. Typically, wood is the preferred fiber. The panels or boards are made by mixing fiber and a binder and then placing the mixture in a hot press. Wood-fiber based composites are sensitive to moisture, particularly moisture in a liquid form. In addition to linear expansion and thickness swell, moisture can cause blistering and fiber-pop at the panel surface. Since fiberboard is often painted or coated, especially for decorative use, blistering and fiber-pop become important issues, especially when using water based topcoats or adhesives. Tempering is often employed to yield a strong surface layer that gives added strength, especially to doorskins used in the manufacturing of doors. During building construction or transport of the finished composite, structural panels are often exposed to weather elements before they are protected by a siding or roofing. Severe weather can cause water damage to unprotected panels in a very short period of time. To protect the paneling during the construction process, a tempering topcoat is sometimes applied to the panel's surfaces to provide them with a hard, moisture resistant surface.

Usually, the process of manufacturing these composite panels includes a use of a tempering oil which is applied to the surfaces of the panel in order to impart a smooth, strong, and water resistant surface thereto. However the manufacturing technology often requires a high temperature bake oven in order to cure the tempering oil after it has been applied to the surface of the panel.

The above described processes have numerous drawbacks, including the release of VOCs, hazardous air pollutants (HAPs), and styrenes. The cost of energy for hot presses or ovens to cure the resins or shape the boards and the carbon emissions from the generation of the energy are additional considerations that motivate seeking an alternative way to make composite building materials.

Although wood continues to be a favored material for boards, and even though wood is one of the most successful renewable resources, the fact is that there simply are not enough big trees in world to satisfy the demand for boards from solid wood. Therefore, smaller trees are chipped and the chips combined with resins and other ingredients to make composite boards in order to meet demand.

There is a need therefore, for a manufactured composite building material that does not rely primarily on wood and that does not require heat curing or pressing and that emits minimal pollutants and other undesirable by-products of manufacture.

SUMMARY

Plant remnants such as pecan shells and rice hulls, instead of wood chips as is typical in the art, provide a substrate for the manufacture of objects such as composite boards and other shapes for use in building construction and industrial uses such a bridges. Mixing such plant remnants with a suitable resin such as a polyester resin catalyzed by MEKP as known in the art yields an amorphous mixture that cures at room temperature (68-90 degrees Fahrenheit). The uncured mixture may be poured into a mold to be shaped into any desired form such as, for example, a counter top, school desk top, vanity top and the like.

The plant remnants appear to interact with the resin in a surprising but poorly understood manner, with the consequence that relatively little resin is required as compared with the amounts of resin typically used for wood chip particle board. A further advantage over wood is that the present mixture in not moisture sensitive and does not need to be dried prior to curing. Yet the fully cured composite mixture displays remarkable strength and stability making it a useful building material. The ability of the composite mixture to cure in a mold at room temperature allows the composite to be put to a wide variety of uses.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a schematic illustration of a process flow of a specific embodiment for a composition of the present disclosure.

DETAILED DESCRIPTION

Referring to FIG. 1, the reference numeral 100 generally designates a process embodying features of a specific embodiment of the present disclosure. The process 100 includes providing an effective amount of post-harvest plant remnants 102 such as rice hulls and pecan shells. Such plant materials are generally farm and agricultural remnants. For the purpose of this disclosure, the phrase “agricultural remnants” refers to non-wood plant materials, to distinguish the plant materials of the present disclosure from the wood chips used in particle board and the like.

Thickeners 104 such as Garamite® and Non-Chloride Accelerator (NCA) are provided. Garamite® is a clay-based Theological additive or thixotrope available from Southern Clay Products, Inc. of Gonzales, Tex. NCA is a concrete additive available from Fritz-Pak™ of Mesquite, Tex. According to the manufacturer's description, Fritz-Pak™ NCA is a non-chloride accelerator in powdered form. It shortens set times while increasing early compressive strength. Fritz-Pak™ NCA does not contain calcium chloride or any other materials that promote corrosion in steel or efflorescence in concrete. Unlike some other non-chloride accelerators, such as those containing calcium nitrite, Fritz-Pak™ NCA is not hazardous. No special handling, storage or transportation expense is required. Fritz-Pak™ NCA is compatible with most concrete admixtures. The effectiveness of NCA is dependent on the proportion of C3A to SO3 in the cement. Higher acceleration will be obtained in cements with ratios greater than 4.0. In general, higher accelerations will be obtained in mixes with Type I, III or white cement. Additionally, additives 106 such as calcium carbonate and antimony trioxide (ATH) in 60% solution by volume may be provided.

For example, the dry mix may constitute the following effective approximate amounts:

Refill (cottonseed husks fines) 1.0 lbs to 3.2 lbs Pecan shells (fines) 1.0 lbs Rice Hulls or peanut shells (fines) 6 oz Wheat >1 oz Garamite 2.3 oz NCA 8 oz Calcium Carbonate (“CC”) 8 oz ATH 9.03 oz LT 9 lbs

Alternative embodiments may selectively incorporate effective amounts of the following components: plastics such as for example Polyetheretherketone (PEEK), poly(ethylene terephthalate) (PETE or PET), and Polytetrafluoroethylene (PTFE or Teflon®) and combinations thereof; recycled plastics; peanuts shells; soy beans; cotton husks; fiber glass matting; E-glass; Q-cells; mineral such as for example talc, cobalt, titanium dioxide, graphite, hydrocal clay, and wollastonite; as well as pigments or colorings such as food coloring and so forth.

Plant remnants 102 as described above may be blended with polyester resins 108 such as unsaturated polyester resin in styrene. Polyester resins may be introduced in the approximate effective amount of 3.47 to 4 lbs for the above amounts of dry mix. Preferably MEKP is introduced in a proportion of approximately 0.75% of the mixture by volume to achieve the desired state of equilibrium. Dry pigment may be added if desired in amounts of approximately ½ cup or 4 oz, for example. Blending maybe accomplished by mechanical means with a blender or by hand with blending paddles. The final weight of batch with dry mix and resins from the above recipe is about 3.3 lbs.

The silica dust fiber refill (cottonseed husks as described above) gives the substrate its base. Cottonseed husk fines may generate natural strands from silica dust naturally present in the husk fines from west Texas. The strand so produced may be similar to fiberglass. To this refill base was added three types of pecan shelling and other agricultural farm fill remnants. For example, pecans from Texas include native, papershell and mayham varieties. Farm fill remnants may include but are not limited to cottonseed hulls, rice hulls (Texas rice hulls, for example, are observed to puff up 5× larger than their original size under the proper circumstances), peanut shells, soybean husks, maze (adds pigment to the mix) corn stalks and the like.

Initiated by the blending process, the refill and plant remnants begin a self-catalyzed anastomose reaction that binds the composites. The Garamite brings the dry mixture to equilibrium and enhances the binding of the plant material. When blended correctly the dry blend will clump. The NCA is added to increase the cure time and provide the accurate timing of curing. If curing is to fast it will disrupt the resin blends but if curing is too slow it will reach a peak temperature and blister. A properly blended mixture obtains natural fire retardant properties.

The mixture takes on its own matrix characteristics as the viscosity increases during stirring. The addition of ATH imparts fire retarding properties and assists in the concentration of the (isophthalic) polyester resin 108. Preferably, the addition of an effective amount of cobalt accelerates the MEKP catalyst to preferred levels and catalyzes the resin 110. Mixing generates heat which elevates to a peak and then stabilizes as the resin/plant remnant mixture sets into a fixed or hardened state.

The composite mixture of plant remnants and activated resin may be molded 112 to a desired form prior to curing of the resin. For example, the mixture may be molded to be a kitchen counter top, vanity table top, or even a building structural support such as a wall or partition. The molds for such purpose may utilize release agents such as automobile wax compounds which may preferably be applied to the surface of the mold three times for ten minute periods each. The repeated applications allow the wax to set up a barrier that will not allow the plant remnant mixture to break through.

Resin Transfer Molding (RTM) 112 accomplishes the curing of the product formula without the application of external heat. RTM 112 is a molding process that involves the transfer of the catalyzed resin/remnant mixture to an at least partially enclosed mold and allowed to cure within the mold, preferably at room temperature. That is, without the application of heat to the mold. Preferably the interior surfaces of the mold have been wax treated as described above to facilitate removal of the cured shape after curing. Upon completion of curing within the mold, the mold may be opened and the cured plant remnant product may be removed for further processing. RTM 112 molds may be hinged or otherwise openable for easy opening and ref-use or, alternatively, some types of molds may have to be shattered to remove the cured product.

RTM 112 may be performed at ordinary pressures but, as specifications may demand, may alternatively be performed under high applied pressure or partial vacuum low pressure. A breather material may be utilized to provide a path for the release of entrapped air from the resin during the curing process, particularly under regular or high pressure curing. Such a breather, for example, may be a loose woven material such as burlap or gauze that does not come in contact with the resin/plant remnant mixture and which extends from the interior of the mold to an outlet vent of the mold to facilitate the escape of gas that might otherwise cause undesirable bubbles in the mixture.

The curing process does not require external heat. The product typically does not blister and so generally reliably produces surfaces that can be treated, and used for a great variety of purposes. For counter tops and the like, for example, a smooth, cleanable surface is preferred. To obtain such a surface, Shower curtain with prisms can be applied on to the cured product and allowed to set to provide a finished product with prism.

A solid barrier against contaminants and dirt. Typically, gelcoat may be a polymer resin that, once it has cured, may be polished to a high polish for kitchen or bathroom counter tops or otherwise suitably textured for a particular application. The gelcoat may also be colored to obtain the appearance of faux materials such as marble or granite.

No gel coat is added to Tula Mixture because material makes her own shine. This makes her a Natural Green material.

Additional additives to obtain particular properties may include but are not limited to e-glass, for example, to achieve a tack free state that the industry calls “B′ Staging.” Additives such as catalyst inhibitors, flame retardants and others as described herein may be introduced to obtain specific end-use properties and improve the over all processing, and handling characteristics of the product.

The amorphous arrangement of the pant remnants in the mixture imbues the matrix of the mixture with increased strength (relative to a typical strand or particle board) inside the mold. The finish product achieves surprising strength as measured in a variety of ways.

Strength Testing Results

Testing has paced Trula Green Material in the Stainless Steel are of testing at 17,000 PSI.

The following section summarizes the test methods and results regarding the materials characterization by an independent testing service of three different composite boards of the present disclosure. Provided herein are a brief description of the test methods as well as a summary of the results obtained.

Material and Specimen Geometry

Three different composite boards were tested. Specimen geometry was dictated by the appropriate ASTM Standard with a total of three replicate tests performed per each test type (18 total tests). The as-received thickness was evaluated during this effort with no thickness alteration. Prior to testing, all specimens were dimensionally measured for subsequent post-test calculations. The tensile testing was performed per ASTM D638 with a tensile “dog-bone” geometry utilized during the effort. Compression testing utilized square 2-in. by 2-in. “pucks” excised from the supplied composite boards and was performed in the spirit of ASTM D695. Lastly, the flexural testing (ASTM D790) utilized 2-in. wide strips cut nominally 16-in. long from the boards. Overall, it is important to note that the relative size of each coupon was substantially larger than any constituent making up the composite boards; this is crucial when evaluating the material properties to gain a global behavior.

Test Procedures

Given the unique nature of these materials, testing was performed in the spirit of the previously mentioned standards. A best effort was made to test to the associated standards.

Tensile testing utilized a servohydraulic test frame with hydraulic clamping grips used to secure each end of the specimen during loading (FIG. 4). Testing was performed at a constant displacement rate of 0.5-in./min. Data, needed for post-test processing, included continuous load and displacement voltage. At the conclusion of testing, the data were processed to determine the ultimate strength for each specimen tested.

The compression and flexural testing utilized an electromechanical test frame with the required fixturing integrated into the frame. With regards to the compression testing, opposing steel platens were used with the specimen placed between each during testing. Testing was concluded upon catastrophic failure. During each test continuous data was recorded for each test and subsequently analyzed to determine the compressive strength. The flexural testing utilized a 4-point configuration with the ultimate goal in determining the flexural properties for the three different composite boards. Testing was concluded upon specimen failure. All testing was performed in lab-ambient conditions; nominally 72° F. and 30-50% RH. No controlled conditioning was performed prior to testing. Each board had ample time to fully cure.

Results

Tensile

The results of the tensile testing are presented in Table 1. When comparing the three composite boards associated with this test effort, the average tensile strengths are comparable at near 1,200 psi. Board #2 demonstrated the highest average strength at 1,283 psi, with Board #3 demonstrating the lowest at 1,145 psi.

Compression

The compressive strength results are presented in Table 2. Similar to the tensile results, the compression strengths are similar at near 6,500 psi. As with the tensile test results, Board #2 demonstrated the highest compressive strength at 6,614 psi.

Flexural

The flexural properties for each board are presented in Table 3. While the flexural strengths are relatively close with regards to the three boards, there appears to be an inherent difference in flexural strength, with Board #1 having the highest flexural strength at 2,720 psi and Board #3 having the lowest at 2,230 psi.

The overall response of the three boards characterized indicates the tensile strengths, compressive strengths, and flexural strengths are nominally similar for each condition. The flexural tests demonstrated the most spread when comparing the three boards, but overall the strength values were comparable.

TABLE 1 Summary of tensile results. Average Failure Failure Failure Material Specimen Thickness, Width, Load, Stress, Stress, ID ID in. in. lb psi psi 1 T-1-1 0.6850 0.8310 731.0 1,017.0 1,195 T-1-2 0.9095 0.8185 723.5 971.9 T-1-3 0.8570 0.8155 1115.5 1,596.1 2 T-2-1 0.8655 0.8305 918.5 1,277.6 1,283 T-2-2 0.8630 0.8355 972.0 1,348.1 T-2-3 0.8405 0.8255 848.5 1,222.9 3 T-3-1 0.8590 0.8280 886.5 1,246.4 1,145 T-3-2 0.6895 0.8215 857.5 1,173.5 T-3-3 0.8445 0.8270 708.0 1,013.7

TABLE 2 Summary of compression results. Failure Failure Material Specimen Area, Load, Stress, Average Failure ID ID in.² lb psi Stress, psi 1 C-1-1 1.0792 6696.9 6,205.5 6,447 C-1-2 1.0353 6464.1 6,244.7 C-1-3 1.0609 7309.4 6,689.9 2 C-2-1 1.0306 6547.5 6,353.3 6,614 C-2-2 1.0622 7224.7 6,801.4 C-2-3 1.0460 6995.6 6,687.9 3 C-3-1 1.0587 7464.6 7,050.5 6,446 C-3-2 1.0518 6602.7 6,277.3 C-3-3 1.0748 6461.0 6,011.1

FIG. 3. Summary of flexural results. Flexural Strain Average Flexural Material Specimen Thickness, Width, Failure Load, Failure Stress, Average Failure at Failure, Strain at Failure, ID ID in. in. lb psi Stress, psi in./in. in./in. 1 B-1-1 0.8813 1.4863 313.1 2,847.4 2,720 0.0039 0.0036 B-1-2 0.6872 1.4927 292.8 2,616.9 0.0034 B-1-3 0.8869 1.4808 298.9 2,695.2 0.0035 2 B-2-1 0.8718 1.4900 266.2 2,467.8 2,469 0.0039 0.0036 B-2-2 0.8495 1.4957 270.8 2,634.5 0.0039 B-2-3 0.8510 1.4682 236.6 2,304.9 0.0037 3 B-3-1 0.8590 1.4610 251.3 2,414.4 2,320 0.0042 0.0042 B-3-2 0.9028 1.4787 254.2 2,214.8 0.0043 B-3-3 0.8497 1.4937 239.5 2,332.0 0.0040

On the basis of the test results, a specimen of an exemplary embodiment of the cured composite of the present disclosure exhibits greater mechanical strength than a comparable weight of concrete, standard particle board or strand board. Indeed, the strength of the present material was so great it broke the testing equipment in one test. Yet the present material is substantially lighter than the same volume of concrete.

Fire Testing

Additional testing was performed by the present inventor. For example, to analyze the product's response to fire, a fully cured specimen was soaked in gasoline for twenty four hours and then ignited. The integrity of the product was observed and recorded.

In the first such test, the specimen soaked in gasoline for one week and was then placed into a metal trash can lid and sprayed WD 40 to enhance ignition. Once ignited the specimen was sprayed with WD 40 until a well define flame formed. The flame was maintained for approximately 20 minutes. Alternatively, the gasoline was ignited by depositing a flaming napkin on the gasoline-soaked specimen.

Another fire test consisted of exposing a fully cured specimen to blow torch at approximately 1400 degrees Fahrenheit for five minutes.

In each case, no cracking, no blistering, no off gassing as vapors, and no brittleness was observed in the specimen. After the gasoline burned off the product did not appear to have shrunk (although no measurements were made) or dry out. No cracking of the product was seen and it was cool to the touch. The product did show signs of smoke damage which may be an artifact of Total Petroleum Hydrocarbon (TPH) remnants.

A further fire test was performed to try to ignite the dry product by placing it directly five inches above a flame and twisting it between the fingers to see what reaction would take place. The dry mixture did not spark or ignite. This results suggests that the product could withstand oxygenate heat transformations and may be useful as a fuel intake conduit.

Bleach Testing

The present inventor also tested the product with bleach by soaking a fully cured specimen in 20 ounces of household bleach in a stainless steel container overnight. The product was observed the next day after soaking approximately 19 hours. The initial observation was the specimen had not shrunk or swelled. It was also observed that some flecks of the plant remnant material along the surface appeared to be loosened or to have come off to be floating in the bleach. The specimen was otherwise still in tact.

The specimen was checked again approximately nine hours later. More pecan remnants and the like appeared to have sloughed off the surface but the specimen showed no blistering. The NCA was exposed with a hair like in appearance. This particular test sample contained PTFE, which was intact in concentrated particles. The bleach took on a darkened color from the pecans in the specimen. The specimen was dropped from a height of approximately 3 feet and did not break.

Bleach is a caustic compound that attacks organic matter. It also weakens cellulose fibers from lignin (a complex polymer and the chief non-carbohydrate constituent of wood. Lignin binds to cellulose fibers to harden and strengthen cell walls of plants). Accordingly, bleach may break down the hearthstone portion of wood into pulp. In the specimen the bleach appeared to affect the dihydroxy alcohols of the resins. Other than loosening the outer surface of plant remnants (pecans), the plant portion of the product held up to the beach exposure. This surprising in view of bleach's known ability to degrade wood.

Sulfuric Acid Testing

In addition to bleach, the present inventor tested the product with another caustic, namely sulfuric acid. A specimen was soaked for eight hours in 20 ounces of approximately 40% sulfuric acid in a five gallon bucket.

Observation of the specimen after eight hours yielded essentially the same results as with the bleach. The specimen likewise did not break after being dropped from approximately three feet.

The composite material of the present disclosure may be formed into a great variety objects because the pre-cured liquid mixture can be poured in a mold having any desired shape. Furthermore, the components of the mixture can be varied so that the cured product resembles granite, marble, concrete and many other familiar construction and industrial materials. Like marble and granite, a cured product from the composite material can be polished to a high gloss for decorative uses. However, unlike stone materials, a product of the present composition weighs much lass than stone of the same size, is easier to transport and is less brittle than stone.

Cured composite products of the present disclosure may be used in house construction as, for example kitchen and bathroom countertop material. Indeed, entire houses or buildings could be manufactured from products formed from the present composite material. An important use of the cured composite is as roofing material to provide buildings and dwellings with strong, light-weight and, most significantly, light-colored roofs. Traditional roofs are often weather-proofed with black tar and dark-colored weather shingles and the like, which contribute to local environmental warming, which in turn may lead to increased atmospheric greenhouse gases from increased energy production for air-conditioning and other climate control measures. Green building practices are increasingly moving toward light-colored roof materials as a way to save energy and reduce greenhouse gases in the atmosphere.

Other uses include parking bumper blocks, road barriers and traffic dividers. In fact road surfaces, particularly for bridges or over passes can be made from the present composite material with significant advantages over concrete and asphalt. For instance, a block manufactured from the composite material for use as a segment of bridge road surface can be formed with gratings, slots and the like to channel water and other run off for improved driving surface conditions. A significant advantage of using the present composite material as a road or bridge surface is that run off contaminants are greatly reduced and less hazardous than are run off contaminants from concrete and asphalt.

The present composite material can be recycled. For example, excess or discarded amounts of the cured composite may be ground down in chips or particles which are added into a virgin mixture where it simply becomes another component of the mixture that is poured into a mold and cured to form an object. Another form of recycling the composite is to add chips and particles of discarded composite back into the fields of farmers as a form of mulch.

Many modifications and other embodiments of the disclosure will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

1. A solid composite material suitable for construction and industrial uses, the material comprising an effective amount of assorted agricultural remnants bound in an effective volume of cured resin.
 2. The composite material of claim 1, wherein the agricultural remnants comprise rice hulls.
 3. The composite material of claim 1, wherein the agricultural remnants comprise pecan shell fines.
 4. The composite material of claim 1, wherein the agricultural remnants comprise cotton seed husk fines.
 5. The composite material of claim 1, wherein the agricultural remnants comprise peanut shell fines.
 6. The composite material of claim 1, wherein the resin comprises a polyester resin.
 7. The composite material of claim 1, wherein the agricultural remnants comprise cotton seed husk fines, rice hulls, and pecan shell fines and the resin comprises a polyester resin.
 8. The composite material of claim 7, wherein peanut shell fines replace the cotton seed husk fines.
 9. A method for making an object from a composite material, the method comprising the steps of: preparing a dry mix containing effective amounts of cottonseed husks fines pecan shells fines rice Hulls garamite Non-Chloride Accelerator (NCA) calcium carbonate and antimony trioxide (ATH); LT blending the dry mix into an effective amount of a liquid resin; adding an effective amount of a catalyst that catalyzes at approximately room temperature to form a fluid composite mixture; pouring the fluid composite mixture in to a mold; curing the fluid composite mixture at approximately room temperature to form a solid cured composite material; and removing the cured composite material from the mold.
 10. The method of claim 9, wherein peanut shell fines replace the cotton seed husk fines in the dry mix.
 11. The method of claim 9, comprising effective amounts of one or more of the components selected from the following: plastic; recycled plastic; peanuts shells; soy beans; cotton husks; fiber glass matting; E-glass; Q-cells; minerals, and pigments and combinations thereof.
 12. The method of claim 9, wherein the plastic or recycled plastic comprises one or more plastic selected from the following: Polyetheretherketone (PEEK), poly(ethylene terephthalate) (PETE or PET), and Polytetrafluoroethylene (PTFE or Teflon®) and combinations thereof.
 13. The method of claim 9, wherein the minerals comprises one or more mineral selected from the following: talc, cobalt, titanium dioxide, graphite, hydrocal clay, and wollastonite and combinations thereof.
 14. The method of claim 9, wherein the catalyst comprises MEKP.
 15. The method of claim 9, wherein the dry mix further comprises an effective amount of wheat. 